In many radio frequency (“RF”) devices, an RF waveguide in a first metal piece can be connected to an RF waveguide in a second metal piece. The connection can also be described as an electromagnetic interface. It may be desirable that this electromagnetic interface be a low Voltage Standing Wave Ratio (“VSWR”) interface. In order to have such a low VSWR interface, it can be advantageous to have uniform contact between the interfacing surfaces of the two metal pieces. With reference to FIG. 1, an electromagnetic interface can be formed between a first metal piece 110 and a second metal piece 120. Although described herein as first and second metal pieces, the first metal piece can more generally be a component, and the second metal piece can more generally be a component, to the extent that these components each comprise a waveguide channel. Thus, an electromagnetic interface can be formed between a first component 110 and a second component 120.
The electromagnetic interface between pieces 110 and 120 defines an interface plane. First metal piece 110 can comprise a waveguide channel 112 aligned in a first direction that can be perpendicular to the interface plane. The second metal piece 120 can comprise a waveguide channel 122 aligned in the first direction as well. The waveguide channels 112 and 122 can be aligned with each other. The first and second metal pieces can be held together by two or more screws 130 that pass through the first metal piece and screw into the second metal piece to keep the two metal pieces in tight contact one with another. In this manner, the two wave guide pieces can be directly fastened to each other. In such embodiments, electromagnetic chokes can be used to improve performance/reduce loss.
However, such direct compression techniques are not always possible due to space constraints, access needs, tool access needs, machining and manufacturing needs, material dimensions, and the like. Improved methods and designs are now described for indirect compression techniques.
In an example embodiment, an electromagnetic interface can comprise: a first component comprising a first waveguide channel, a first interface surface, and a first force transfer feature; a second component comprising a second waveguide channel, a second interface surface, and a second force transfer feature; and a fastener that can be configured to force the first force transfer feature in sliding engagement with the second force transfer feature. The first and second force transfer features can be configured to interoperate, to create an indirect force holding the first interface surface in contact with the second interface surface and holding the first waveguide channel in alignment with the second waveguide channel.
In another example embodiment, an electromagnetic interface can be configured to have a low voltage standing wave ratio at the electromagnetic interface between two components using an indirect force to engage the two components. The electromagnetic interface can comprise: a first force transfer feature in fixed spatial relationship with a first component of the two components; a second force transfer feature in fixed spatial relationship with a second component of the two components. The first force transfer feature and second force transfer feature can be configured to convert the indirect force in a first direction into a direct force in a second direction. The direct force in the second direction can cause the first component and the second component to be held together at their EM interface.
A method of connecting a waveguide to a chassis can comprise: forming a waveguide comprising a first force transfer feature; forming a chassis comprising a second force transfer feature; and applying an indirect compression force between the waveguide and the chassis. The indirect compression force can be translated through the first and second force transfer features to generate a compressive force that can hold the waveguide and chassis together at a waveguide interface.